This application discloses a method and control for determining the relative sizes of the ducts leading to each of several zones in a multi-zone HVAC system.
Multi-zone HVAC systems are known, and include a component(s) for changing the temperature and condition of air (a furnace, air conditioner, heat pump, etc.). For simplicity, these components will be referred to collectively as a temperature changing component. Also, an indoor air handler drives air from the temperature changing component through supply ducts to several zones within a building. Each of the supply ducts typically have dampers that may be controlled to restrict or allow flow of air into each zone to achieve a desired temperature.
In these systems, sizes of the ducts leading to each of the zones may vary due to restrictions, etc. which could occur along the length of the ducts. Thus, while modern HVAC systems are being adapted for the consideration of sophisticated controls, accurately controlling the flow of air into each of the several zones would require knowledge of the relative sizes of the ducts. As an example, if there were two ducts leading to two zones, with one of the two ducts being smaller than the other, the smaller duct would tend to receive less airflow than the larger duct. Knowledge of the sizes of the ducts is thus important, to provide the ability to achieve close control over airflow to these zones.
However, no method of determining the duct sizes to each of the zones is known in the prior art. At best, an installer could manually measure the duct sizes. However, this would be relatively impractical, and has not been utilized.